Apparatus and method for lining in situ pipe

ABSTRACT

Apparatus for driving a flexible composite liner into an existing pipe in an excavation comprises contra-rotating wheels for driving flexible liner therebetween and into a guide tube extending between the driving wheels and the existing pipe. The guide tube forms a curved path to align the liner with the existing pipe. A port is formed in a linear portion of the guide tube enables insertion and connection of an optional inflexible bullet to the leading end of the flexible liner. The drive wheels are preferably assisted by transverse guide wheels. The existing pipe is exposed in an excavation. A trailer with the drive wheels is positioned adjacent the excavation, a guide tube is installed to extend between the trailer and the existing pipe forming a curved path, a spool of flexible liner is provided and driven through the guide tube to be aligned with and inserted into the existing pipe.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for remediation of in situ existing pipelines and more particularly to inserting a flexible fiberglass-reinforced composite liner into an existing pipeline.

BACKGROUND OF THE INVENTION

Pipelines which carry fluids are susceptible to deterioration, corrosion and other conditions which seriously affect the lifespan of the pipe. Excavation of a pipeline or pipe, to replace sections that have deteriorated, is costly and often detrimental to the environment.

In situ pipelines of pipe typically build corrosion and scale on an inner surface, over time. The buildup within the pipe bore acts as a barrier to insertion of the liner. Large pipes can be cleared using pigging techniques, however smaller diameter pipes do not lend themselves to this type of cleaning technique. U.S. Pat. No. 4,827,553 to Turpin Sr. et al teaches passing a pipeline scraper into the bore of a pipeline and reciprocating the scraper back and forth on lengths of cable to remove residue from the bore of the pipeline.

It is known to excavate down to a portion of the pipeline from surface, sufficient to gain access to the bore of the pipe, and insert a plastic liner into the bore of the existing, in situ pipe to prevent leakage as a result of deterioration. Typically, liner is pulled through an existing pipe at the end of a threaded cable or the like, previously installed with conventional steel rods.

Due to the unwieldy lengths of liner that are required, the supply of liner is provided at surface and must be fed into the excavation down into the bore of the pipe. Due to the angle of the minimal excavation and the usual horizontal plane of the in situ pipe, the orientation and insertion of inflexible liners presents a challenge.

As taught in U.S. Pat. No. 4,504,171 to Florence Jr., conventional malleable liners for underground pipes are often thick and relatively stiff. In order to insert the liner into the pipe, from a point above the pipeline, the liner must first be plastically deformed, using an installation tool comprising deforming rollers, to provide a distal curve in the liner. The liner is also deformed to form a proximal curve to direct the liner downward into the excavation, while the distal curve directs the liner generally toward the pipeline. The deforming rollers are also used as drive rollers to advance the liner into the pipe.

It is known to use a roller assembly coupled directly to an old pipe and aligned in co-linear arrangement thereto so as to insert flexible plastic pipe straight into a pipe, such as that disclosed in U.S. Pat. No. 4,300,276 to Davis. Lower rollers having an annular groove and a gripping surface, such as rubber, act to guide and support a flexible pipe. The lower rollers are connected in driving relation to each other by a drive chain. Upper rubber rollers, having an annular groove, engage the upper surface of the pipe opposite the lower rollers. The rollers are arranged in-line with the pipe to avoid bending of the flexible liner. The apparatus must be placed into close proximity with the pipe to be lined, including in an excavation around the pipe itself. Also, U.S. Pat. No. 3,546,890 to Ede teaches use of an apparatus lowered into an excavation adjacent an opening and comprising three rows of motor-driven rollers having pneumatic tires as thrusting means to advance a steel pipe into the opening formed by a mole plough.

More recent development of spoolable, elongated flexible liners, such as continuous composite line pipe, (FIBERSPAR® LinePipe™ from Fiberspar Corporation, West Wareham, Mass., USA) has provided an alternative to the more inflexible varieties of liner. Particularly when a large axial force is required to advance the liner, difficulties in handling are increased due to the flexibility of this type of liner—its is difficult to push a rope. Further, the composite nature of the liner does not permit overly rough handling.

Ideally it is desired to minimize the process of cleaning and insertion to, if possible, a single operation and without the complication of entering the excavation. What is required is apparatus that, while capable of inserting flexible liner from a point above the pipeline, can also accept an inflexible pipeline scraper of sufficient diameter to successfully ream the inside of the pipeline to accept a new liner.

SUMMARY OF THE INVENTION

In a preferred embodiment of the invention, a convenient and efficient apparatus is provided for driving a flexible composite liner from above an excavation into an existing pipe exposed in the excavation. Applicant has solved the conflicting objectives of pushing a flexible liner, preparing the existing pipe with a robust inflexible element and inserting the less robust flexible liner in the prepared pipe. Applicant drives the flexible pipe with a drive positioned remote and above from the existing pipe and guiding the liner through a curved guide tube so as to align a linear portion of the discharge end of the guide tube with the existing pipe. Where the existing pipe needs to be first prepared to receive the liner, an inflexible bullet can be inserted into the linear portion and connected to the liner prior to driving and inserting the liner into the existing pipe.

In one broad aspect of the invention, apparatus is provided for inserting a flexible liner into the bore of an existing in situ pipe, the apparatus comprising: a drive positioned at an elevation above the pipe for pushing a flexible liner in the bore of the pipe, the drive having at least a first pair of contra-rotating resilient drive wheels having a nip formed therebetween through which the flexible liner is frictionally driven; a transverse support for restraining the flexible liner in the nip; a drive motor connected to drive at least one wheel of the first pair of contra-rotating drive wheels; a guide tube extending between the drive and the bore for flexing and guiding the liner from above the pipe into the bore.

Preferably, the guide tube is curved for aligning a liner which is supplied at an angle to the existing pipe, and more preferably extends along a path between the pipe, exposed in an excavation, to an elevation above the excavation. The guide tube preferably has a linear portion adjacent the pipe for the insertion of inflexible elements such as a bullet for connection to the leading end of the flexible liner. The bullet enables improved preparation of the bore of the pipe before insertion of the flexible liner following the bullet.

The apparatus enables a unique methodology for the insertion of a flexible liner, the supply of which is remote from the existing pipe. A method comprises positioning a guide tube between the drive and a bore of the existing pipe; guiding the liner along a curved path from a point above the existing pipe into the bore, the guide tube having a linear portion being aligned with the bore and driving the flexible liner for inserting the bullet and flexible liner into the existing pipe. Preferably before inserting the liner the method further comprises inserting a non-flexible bullet is into the port; and connecting the bullet to the flexible liner at the port for cleaning the existing in situ pipe ahead of the liner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic side view of apparatus and a method of installing liner according to one embodiment of the invention;

FIG. 1 b is a perspective view of the drive means and a spool of liner in place adjacent an excavation;

FIG. 1 c is an alternate embodiment of a guide tube, substituted for the guide tube according to FIG. 1 a;

FIG. 2 is a schematic diagram of a drive for a flexible liner and a guide tube according to FIG. 1 a;

FIG. 3 is a closer view of the drive of FIG. 2 and also illustrating a plan view of the drive;

FIG. 4 is a perspective view of a drive apparatus manufactured according to another embodiment of the invention;

FIG. 5 is a perspective view of an excavation exposing a pipe fit with a guide tube for rehabilitation with a liner according to the invention;

FIGS. 6 a and 6 b are a partial perspective views of a steel rod and of a grapple engaging the upset end of a steel rod for winching from a pipe; and

FIG. 7 is an alternate embodiment of the drive apparatus and system for injecting spoolable composite tubing into a wellbore.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Having reference to FIG. 1 a, apparatus 10 is provided to frictionally drive a flexible liner 12 from an elevation above an excavation 13, into and through an exposed end of an in situ pipe 14, located at a lower elevation such as adjacent a bottom of the excavation 13. The apparatus 10 comprises drive means 15 and a guide tube 16 extending between the drive means 15 and the pipe 14. The drive means 15 need not be aligned with the pipe 14.

The drive means 15 provides sufficient thrust to advance the flexible liner 12 through the guide tube 16 and through the pipe 14. The guide tube 16 is sufficiently rigid to elastically direct the liner through the guide tube between the drive means 15 and the pipe 14.

Generally, a flexible continuous composite line pipe is typically 2 inch diameter from FIBERSPAR® LinePipe™ from Fiberspar Corporation, suitable to line 4 inch diameter pipe 14.

Best seen in FIGS. 2, 3 and 4, the drive means 15 comprise at least a first pair of contra-rotating drive wheels W1 which form a nip N through which the flexible liner 12 is driven. To ensure sufficient frictional engagement, at least one wheel W1 of the first pair of drive wheels is resilient and preferably both are resilient pneumatic tires inflated to about 70 psi, and rotated at about 24 rpm. At least one of the wheels W1 is rotatably connected to a motor 20, preferably a hydraulic motor powered with by a gas-powered engine 21. A suitable system includes a 20 Hp engine 21 coupled with 12 USgpm, 1850 psi hydraulic motor 20. In testing, such as system is capable of driving a 2 inch composite tubing liner at least 750 meters through old pipe. Higher capacity drives means 15 includes use of a hydraulic splitter or lock-up differential for ensuring slippage of one of the wheels W1 is avoided. Further, multiple pairs of drive wheels can be used for increased capacity.

The drive wheels W1 are mounted onto a frame 22. As the drive wheels W1 are rotated, the flexible liner 12 is advanced through the nip N and along a path P that is angled from horizontal, so as to direct the flexible liner 12 into a bore of the guide pipe 14 in the excavation 13 below. Preferably, the flexible liner 12 is provided in a continuous length, more preferably, wound onto a spool 24.

With reference to FIG. 1 b, a tractor trailer supporting a spool is oriented to feed liner 12 to the drive means 15, positioned adjacent an excavation 13 with the guide lube 16 descending for delivery of guided liner 12 into the excavation.

Best seen in FIG. 3, guide means, such as a rollers or at least one pair of contra-rotating guide wheels W2,W2 are oriented substantially at right angles to the plane of the drive wheels W1, ensure that the flexible liner 12 is guided and stabilized in the nip N. While wheels W1,W1 are shown herein as being driven, equally possible is to drive wheels W2,W2.

With reference to FIG. 4, and in the preferred embodiment, the frame to which the apparatus is mounted is a portable frame 30, such as a trailer. A single pair of contra-rotating drive wheels W1 are mounted, on a sub-frame 31, along the path P of the flexible liner 12 and are oriented having a drive axis 32 perpendicular to the path P. Two pairs of guide wheels W2,W2,W2,W2 are illustrated are mounted perpendicular to the drive wheels W1,W1, a first pair W2,W2 in front of the drive wheels W1,W1 and a second pair W2,W2 behind the drive wheels.

The liner 12 is guided into the drive and guide wheels W1,W2 with a delivery tube 26. The delivery tube accepts flexible liner from the spool 24 and delivers it to the nip N. Pushed liner 12 is directed into a discharge tube 27 which is adapted for connection to the guide tube 16.

In a preferred embodiment of the invention, as shown best in FIGS. 1 and 5, the guide tube 16 is adapted for direct attachment to an exposed end of the in situ pipe 14. The guide tube 16 acts to guide the flexible liner 12 along a path into the bore of the pipe 14. The guide tube 16 may be continuous or sectional and has a first connection to the pipe 14 and a second connection to the drive means 15.

In FIG. 1 the guide tube 16 is formed of sections of metal pipe. A plurality of straight sections and curved sections can be combined to adjust for elevation and angle. Guide tube sections can be connected with means such as a flanges. In FIG. 1 c, a stiff hose can also serve as a guide tube 16. Suitable hose for 2 inch liner is a 4 inch reinforced suction hose with suitable end connecters such as cam locks (not detailed) for connection to the drive means 15 and an ad hoc connection to the pipe 14. A guide tube 16 formed of stiff hose reduces the effort required for aligning pipe 14 and drive means 15.

The supply or source of the liner 12 is typically misaligned or at an angle to the existing pipe 14. This is the case when the liner 12 is supplied from an elevation above the pipe 14. Accordingly, the guide tube 16 is arcuate or curved so as to provide at linear portion 38 at a discharge end having a bore substantially aligned with the bore of the in situ pipe 14 and aligned with the liner coming from the drive means 15.

The apparatus 10 further permits the advance and subsequent retraction of other means for reaming the bore of the in situ pipe such as metal or fiberglass rods of various diameter and surfaces, which can be used prior to insertion of the flexible liner, should the bore of the in situ pipe be badly blocked. Accordingly, it is desirable to utilize a leading device such as a bullet 35 adapted for connection to a leading end 36 of the liner.

As shown in FIG. 2, the substantially inflexible bullet 35 is provided prepare or ream an inner surface of the in situ pipe in advance of the liner as it is pushed thereinto and thereby permits substantially unobstructed advance of the flexible liner therein. As suitable bullet would be a 2{fraction (1/2)} inch diameter steel member for preparing the pipe 14 ahead of a 2 inch diameter flexible pipe. As an arcuate guide tube 16 is normally intolerant of the passage of an inflexible bullet 35, the guide tube 16 is fit with an access port 37 formed in the linear portion 38 which is aligned with the pipe 14 (FIG. 1 a). Alternately, in the case of a stiff hose as a guide tube 16, the connection at the pipe 14 can be temporarily released. The access port is sufficiently long to accommodate bullet 35 through an upper surface of the guide tube 16. The substantially inflexible bullet 35 is inserted into the port 37 and connected to the leading end 36 of the flexible liner 12. Thus, the port 37 solves the problem of attempting to pass an inflexible element through a curved guide tube. Fluids displaced from the pipe 14 can also escape through the port 37. Further, positioning and connection of the bullet at the aligned portion of the guide tube permits the diameter of the bullet to be only slightly smaller than that of the bore of the in situ pipe, improving the bullet's reaming capability therein.

In use, as shown in FIG. 1 a, in one embodiment, the arcuate guide tube 16 is aligned and affixed between the pipe 14 and the drive 15. A source of liner is fed through the drive and into the guide tube 16. The drive 15 pushes the liner 12 through the guide tube 16 and into pipe 14. Preferably a seal of sorts, provided by the bullet when used, is located at the leading end 36 of the liner 12 to the entry of debris. Lubricant can be added at a port or opening 39 at the drive end of the guide tube to aid in the passage of the liner through the guide tube 16. Mineral oil is a suitable lubricant between a metal or oil-resistant stiff hose guide tube 16 and a composite flexible liner 12.

In another embodiment, as shown in FIGS. 1, 4 and 5, the flexible liner 12 is advanced along the angled path P by the drive wheels W1,W1. The drive 15 pushed the flexible liner 12 which enters the guide tube 16, typically adjacent an edge of the excavation 13 for directing the liner 12 downward until the leading end 36 appears in the port 37 in the aligned linear portion 38 of the guide tube 16 adjacent the pipe 14. Once the flexible liner has emerged at the port 37, the inflexible bullet 35 is connected, such as by threads, onto the leading end 36 of the flexible liner 12. Once again the drive wheels W1,W1 advance the flexible liner, thrusting the bullet and the liner into the bore of the in situ pipe 14. The bullet 35 removes any scale built up on the inner surface of the pipe permitting advance of the liner.

Optionally, the operation is conducted in two operations, a first time to advance a reaming member such as flexible fiberglass rods. Once extracted, the flexible liner can be pushed through the conditioned pipe 14. For example, and in a process equally represented in FIG. 1 as for the flexible liner alone, rods 12 a are provided for use with badly scaled pipe wherein the pipe's bore has a greater degree of occlusion, to be passed through the in situ pipe 14 prior to advancing the flexible liner 12 and bullet 35 into the pipe 14. The rods 12 a are relatively flexible and capable of passing through the curved portion of the guide tube 16. The rods 12 a are provided in sections 12 a,12 a . . . , each section threaded for connection to a subsequent section. Further, each section has an upset 50 formed at one end, the upset sized larger than the diameter of the flexible liner 12 and capable of acting against the inner surface of the in situ pipe 14 to remove scale. Sections of rods 12 a,12 a are connected and driven into the in situ pipe using the same apparatus as is used for the flexible liner 12. Preferably, the drive wheels are fit with chains (similar to snow tire chains) to provide sufficient grip against the solid rods. As each section of rod 12 a is driven forward, a subsequent section of rod is threaded onto an exposed thicker upset end 50.

Once the rods 12 a,12 a have been advanced to prepare the entire length of the in situ pipe, it is retrieved from the pipe 14 using a winch. A grapple 51, connected to a winch line (not shown), is connected over the upset end 50 of the last section of rod 12 a and the rod is winched out of the pipe 14 section by section. The grapple 51 has a tubular slotted body 52 which fits over the narrower rod and engages the upset 50 when moved axially along the rod. A loop 53 is welded to the body 52 of the grapple. When the body is engaged with the upset, the loop 53 extends beyond an end of the upset for connection to a releasable connection such as hook 54 at the end of the winch line. The loop 53 is positioned along an axis of the rod which is advantageous for extracting the rod from the pipe 14.

Further, the grapple 51 has a handle 55 connected between the body 52 and the loop 53, to assist an operator with rapid engagement and disengagement of the grapple with each section of rod.

With reference to FIG. 7, an alternate embodiment is illustrated comprising installation of the drive means atop a wellhead 60 of a well 61. A spool 24 of tubing 12 is injected down the wellbore through a seal 62. The guide tube can align the spool with the drive means 15 prior to injection. 

1. Apparatus for inserting a flexible liner into a pipe, the apparatus comprising: a drive positioned at an elevation above the pipe for pushing a flexible liner into a bore of the pipe, the drive having at least a first pair of contra-rotating resilient drive wheels having a nip formed therebetween through which the flexible liner is frictionally driven; a transverse support for restraining the flexible liner in the nip; a drive motor connected to drive at least one wheel of the first pair of contra-rotating drive wheels; a guide tube extending between the drive and the bore for guiding the liner from above the pipe into the bore.
 2. The apparatus as described in claim 1 wherein the transverse support comprises at least one pair of contra-rotating guide wheels oriented at substantially 90 degrees to the at least one of the pair of contra-rotating drive wheels.
 3. The apparatus as described in claim 2 wherein the at least one pair of contra-rotating drive wheels are oriented horizontally in relation to the flexible pipe and the at least one or more pairs of contra-rotating guide wheels are oriented vertically in relation to the flexible pipe.
 4. The apparatus as described in claim 1 wherein the flexible liner is supplied at an angle to the existing pipe and the guide tube is curved sufficiently to form a linear portion for aligning the guide tube with the existing pipe.
 5. The apparatus as described in claim 4 wherein the guide tube is rigid further comprising a non-flexible bullet adapted for connection to a leading end of the liner; and a port positioned in the linear portion of the guide tube for accepting the non-flexible bullet for enabling connection to the leading end of the liner so that the bullet prepare the bore of the pipe for the liner.
 6. The apparatus as described in claim 1 wherein the flexible liner is fiber-reinforced plastic pipe.
 7. Apparatus adapted for inserting a liner into a bore of an existing in situ pipe, the apparatus comprising: drive means for frictionally driving a flexible liner having an inflexible bullet connected at a leading end; an arcuate guide tube positioned between the drive means and an opening to the bore of the existing pipe for guiding the flexible liner from a point above the existing pipe into a linear portion of the guide tube adjacent the opening and being aligned with the bore; and a port positioned in the aligned linear portion of the guide tube for enabling connection of the inflexible bullet to the flexible liner prior to insertion into the pipe.
 8. The apparatus as described in claim 7 wherein the drive means further comprises: at least one pair of contra-rotating drive wheels having a nip formed therebetween through which the flexible linear is driven; a transverse support for restraining the flexible linear in the nip; and a drive motor connected to drive at least one wheel of the pair of contra-rotating drive wheels.
 9. The apparatus as described in claim 8 wherein the transverse support comprises at least one pair of contra-rotating guide wheels oriented at substantially 90 degrees to the at least one of the pair of contra-rotating drive wheels.
 10. The apparatus as described in claim 7 wherein the liner is supplied from above the guide tube and the guide tube is curved sufficiently to align the linear portion with the existing pipe for accepting the non-flexible bullet and for connecting the bullet to the liner.
 11. The apparatus as described in claim 7 wherein the port has a length sufficient to accept the non-flexible bullet and permit connection to the flexible liner.
 12. The apparatus as described in claim 7 wherein the bullet has a diameter larger than the diameter of the flexible liner for removing debris from an internal surface of the existing pipe.
 13. The apparatus as described in claim 7 wherein the flexible liner is fiber-reinforced plastic pipe.
 14. A method of inserting a flexible liner into an existing in situ pipe, the method comprising: providing a drive for driving a flexible liner; positioning the drive spaced from the existing pipe; positioning a guide tube between the drive and a bore of the existing pipe; aligning a substantially linear portion of a discharge end of the guide tube with the existing pipe; and driving the flexible liner through the guide tube for guiding the liner into the existing pipe.
 15. The method as described in claim 14 wherein prior to guiding the flexible liner into the pipe, further comprising connecting the bullet to the flexible liner and then driving the flexible liner and bullet through the guide tube for guiding the liner into the existing pipe driving the flexible liner into the existing pipe.
 16. The method as described in claim 15 wherein prior to guiding the flexible liner into the pipe, further comprising inserting an inflexible bullet into the linear portion of the discharge end of the guide tube for connection to the flexible liner.
 17. The method as described in claim 14 further comprising: driving the flexible liner with at least one pair of contra-rotating drive wheels having a nip formed therebetween through which the flexible pipe is driven; and guiding the flexible liner through the guide tube to the existing pipe.
 18. The method as described in claim 17 further comprising guiding the flexible liner with at least one pair of contra-rotating guide wheels oriented at substantially 90 degrees to the at least one of the pair of contra-rotating drive wheels driving the flexible liner.
 19. The method as described in claim 14 wherein the guide tube is curved, further comprising: aligning the linear portion of the curved guide tube with the existing pipe; and aligning the guide tube with the drive means.
 20. The method as described in claim 14 wherein prior to inserting the flexible liner, the method further comprises: driving a relatively flexible rod through the guide tube and into the existing pipe using the drive means to prepare the bore of the existing pipe; and extracting the rod from the bore using a winch.
 21. The method as described in claim 20 wherein the rod comprises a plurality of sections for forming the rod, each section having a threaded connection for connection to a subsequent section of rod.
 22. The method as described in claim 21 further comprising attaching a grapple to each section of rod prior to extraction of the section, the grapple extending from a body portion of the rod to abut an upset formed about the threaded connection and having an attachment portion for attachment to the winch so as to apply extraction force of the winch along at a central longitudinal axis of the rod.
 23. The method as described in claim 22 wherein each upset is sized larger than the flexible liner so as to prepare the bore of the existing pipe prior to the insertion of the flexible liner. 